In currently known vehicle latch assemblies, a door handle (e.g., an inside door handle) can have a locked, an unlocked and a release position. The locked and unlocked positions are stable positions; that is, when the handle is placed in the locked position or the unlocked position, it stays in that position. However, moving the inside handle to the release position requires the inside handle to oppose a spring biasing force in the latch assembly. The inside handle is therefore unstable in the release position and will return toward the unlocked position when released due to the spring biasing force.
Pulling the handle from the locked position to the unlocked position unlocks the door. Further movement of the handle to the released position then unlatches the door. If the handle is pulled to unlatch the door and then released quickly, there is the possibility that excess spring biasing forces on the handle will cause the handle to move past the unlocked position back to the locked position. This phenomenon is called “snap back” locking and potentially causes customer dissatisfaction.
Although it may be possible to reduce the spring force to prevent the release handle from snapping back past the unlocked position to the locked position, adjusting the spring force is not always possible since the spring forces must still be kept high enough to both resist the inertia of system components during crash deceleration and return all moving elements to their rest positions to ensure full engagement of the latch pawl and claw in the latch assembly. It may also be possible to increase the locking mechanism spring force to counter the spring force in the system, but this would undesirably increase the effort needed to operate a key in the latch assembly.
One suggested solution is described commonly-assigned, co-pending patent application EP1182310, where the “snap back” phenomenon is overcome by using the inertial and/or centripetal forces associated with the handle movement to move an element that is pivotally mounted on the handle. The element prevents the handle from moving to the locked position from the released position.
An object of the present invention is to provide an alternative method of overcoming the “snap back” phenomenon.